Derech HaMelech – if you use wine or grape juice, be careful that it’s not kedushat sh’veet. If it is,, you can’t put the candle out in the puddle (and you shouldn’t have a puddle).
We have cases of grape juice that my wife got on sale, and it’s all kedushat sh’veet. We don’t put the candle out in it, except for last Shabbat – during the nine days we use beer.